The present invention relates to a non-lethal weapon. More particularly, the present invention relates to circuitry which generates voltages and currents sufficient for incapacitation or immobilization of a target. The circuitry may be implemented in a projectile launched from a standard weapon.
Non-lethal weapons intend to temporarily disable a living target, i.e. a person or animal without causing permanent damage. Among possible methods for incapacitation, electrical current is considered relatively safe and practical to implement. In this approach, a pulsating current is injected across a portion of the body tissue of the target. The shape and magnitude of the current are such that the current interferes with the neuromuscular system of the target, and causes a temporary disabling or stun effect. In order to prevent possible interaction between the persons, e.g. who control the non-lethal weapon, and the target, remote operation of the non-lethal weapon is desirable. The electrical incapacitation preferably takes place while the controlling agent is at a distance from the subject. Non-lethal immobilization weapons have been developed with tethers or wires attached between the power source and the projectile.
Electrical pulses used for incapacitation preferably include a high voltage component. High voltage is required to breakdown any gaps in the electrical circuit path that carries the incapacitation signal from the weapon to the target. The presence of the gaps stems from the fact that the electrodes connected to the circuitry may not reach the body tissue of the target due to clothing and/or other obstacles. An electrical breakdown in the gaps generates electrically conducting plasmas which close the electrical circuit between the weapon and the target. Once the electrical breakdown occurs, the electrical circuit conducts from the weapon to the target without galvanic contact between the electrodes and the body tissue. Circuits which first breakdown non-conducting gaps by a high voltage and ionize the gas allowing a current to flow through the gap, are well known dating for instance to early designs of fluorescent lamp ballasts. (See for instance W. Elenbass, Ed. Fluorescent Lamp. UK. London, Macmillan, 1971.) Similar circuits are also used for starting high intensity discharge (HID) lamps such as a sodium HID lamp (e.g. S. Ben-Yaakov, and M. Gulko., Design and performance of an electronic ballast for high pressure sodium (HPS) lamps. IEEE Trans. Industrial Electronics, 44, 4, 486-491, 1997).
U.S. Pat. No. 6,999,295 discloses an electronic disabling device for immobilizing a target including a power supply, first and second energy storage capacitors, and two switches to selectively connect the two energy storage capacitors to down stream circuit elements. Reference is now made to FIG. 1 which is a schematic circuit drawing according to the teachings of U.S. Pat. No. 6,999,295. Two power supplies PS1, PS2 charge two capacitors C11, C12 to respective specified voltages in order to store the energies needed for: (1) generating the high voltage required for breaking down gaps GAP1, GAP2 and (2) to deliver the incapacitating current to the target represented as an electrical load ZL. Capacitor C12 which stores the energy required for (1) generating the high voltage, is connected, via a spark gap SPK2, to the primary n1 of transformer T1 having a secondary high voltage winding n2. Capacitor, C11, storing the energy to (2) deliver the incapacitation current is connected to secondary n2, of transformer T1, via a spark gap SPK1. Both spark gaps SPK1 and SPK2 are initially in the ‘off’ non conducting state. Pulse generation commences when the voltage across C12 reaches the breakdown voltage of SPK2. On breakdown across SPK2, a resonant circuit is closed including capacitor C12 and the inductance of primary n1 of transformer T1. The resonant circuit according to the teachings of U.S. Pat. No. 6,999,295 hence has finite initial energy from the charge stored in capacitor C12. A conduction path which is now enabled by the breakdown across SPK2 builds up a sinusoidal current causing a sinusoidal voltage to appear across the primary of n1. Transformer T1 is built as a step up transformer (n2>n1), and consequently a high voltage appears across secondary n2 of transformer T1 which breaks down gaps GAP1 and GAP2 and spark gap SPK1 along the circuit path. Breakdown in spark gap SPK1, and gaps GAP1 and GAP2 open a conduction path between the voltage across C11 and the target load ZL.